Agent Exchange x402 census and directory

x402 census · sicher.halowerk.com · 3aa0f65b2254 · JSON

POST /v1/webhook-signature

live

Providers each build their signing string differently — some sign only the body, others prepend a timestamp, an id, or a version marker in a fixed order — and getting that order wrong produces a mismatch that looks exactly like an attack. This checks the signature the way the named provider actually specifies, with constant-time comparison, and returns the string that was signed so a mismatch can…

Verdict: live. The unpaid GET reached a valid 402 (confirmed by the re-probe of 2026-10-02).

Facts from the catalogs

FieldValue
URLhttps://sicher.halowerk.com/v1/webhook-signature
MethodPOST
Price$0.002 USDC = 2000 atomic units of 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
Networkeip155:8453 (base)
payTo0x2880EdfFF13100677Bf97A3CBdF3Bc34771C4E5E
Sellersicher.halowerk.com
Catalogscdp (row updated 2026-09-19)
Listed since (lower bound)2026-09-19 (earliest catalog timestamp; catalogs report last-update times only)
Last catalog update2026-09-19
CDP quality counters1 calls and 1 unique payers in 30 days, last call 2026-09-19 (catalog-reported, not verified on chain)
Category (keyword rule)other/unknown
Templated pathno
x402Version in catalog2
Service name / tagsnone

Unpaid probe (census of )

FieldValue
Probenot probed in this build

Latest re-probe

FieldValue
Re-probed at2026-10-02T12:13:42.000Z (cron)
Verdict nowlive changed from unprobed
HEAD / GET402 / 402
accepts[0]{"scheme":"exact","network":"eip155:8453","amount":"2000","payTo":"0x2880EdfFF13100677Bf97A3CBdF3Bc34771C4E5E","asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","maxTimeoutSeconds":300,"extra":{"name":"USD Coin","version":"2"}}
Live amount equals catalog priceyes
Latency2,043 ms
Errornone

On-chain facts for the payTo (public address)

FieldValue
Distinct payers13
Payments94
USDC volume$0.33
Median payment$0.003
First / last payment2026-08-10 / 2026-09-30
Sampler-shaped share of payments98.9%
Payers that are not samplers1
Sourceforensics-2026-09-30
Address0x2880EdfFF13100677Bf97A3CBdF3Bc34771C4E5E (contract: EIP7702StatelessDeleGator)

Declared input and output (extensions.bazaar)

{
 "input": {
  "body": {
   "body": "{\"synthetic\":true,\"event\":\"documentation-example\"}",
   "provider": "github",
   "secret": "HALOWERK-public-synthetic-example-never-use-for-authentication",
   "signature": "sha256=fdfaa7380ce9e369a7d90e8651603bb777a4f008dd3070b056d2b59122d602f8"
  },
  "bodyType": "json",
  "method": "POST",
  "type": "http"
 }
}

Try it (unpaid: shows the 402)

curl -si -X POST 'https://sicher.halowerk.com/v1/webhook-signature' -H 'accept: application/json' -H 'content-type: application/json' --data '{}'

The catalog declares POST. A 402 answer carries the payment requirements in the JSON body and, for x402 v2, base64 in the PAYMENT-REQUIRED header. This page never sends a payment.

Paid checks (x402, USDC on Base)

GET https://bazaar.agentexchange.work/r/3aa0f65b2254/probe.json re-runs this probe right now for $0.01 and writes the result here. POST https://bazaar.agentexchange.work/featured with {"id":"3aa0f65b2254"} places this resource at the top of the report and search pages for 30 days for $1.00, labelled. Unpaid requests answer 402 with the terms. Pricing.

Catalog references: agentic.market (CDP Bazaar front end) · this record as JSON · all resources on sicher.halowerk.com.